Styrene-maleic anhydride copolymers (hereinafter sometimes referred to as "SMA" for brevity) have heretofore been used widely as industrial materials in various fields since they have an excellent heat resistance, and according as their use or application is expanded it is increasingly desired to further improve their glossiness and impact strength.
Japanese Patent Publication No. 7849/80 discloses a method for producing an SMA based resin composition by copolymerizing styrene having dissolved therein a butadiene rubber with maleic anhydride to form a copolymer matrix and dispersing in the copolymer matrix a rubber particle which absorbs a part of the copolymer. However, this method is disadvantageous since it cannot give rise to resin compositions which are excellent in both glossiness and impact strength.
On the other hand, Japanese Patent Publication No. 13541/84 discloses a resin composition comprising a blend of a methacrylate-butadiene-styrene copolymer (hereinafter sometimes referred to as "MBS" for brevity) prepared by an emulsion polymerization method with an SMA. This resin composition, however, has an insufficient impact strength.